Yes you are correct.
But first of all always make sure the fin and lead are a maximum of 2.5 kg.
Then with your boat assembled with the top rig in, the boat should wieh a minimum of 4.0kg. If it is under, add corrector weights to the bottom of the boat ( usually either side of the fin box at point of balance) to bring to just above 4.0kg. This should also include all the electrics and battery as well.
Basically the boat is set up at minimum weight for light airs.
Then as already mentioned put corrector wieghts in the bottom of the 2nd and 3rd rig, so making them weigh the same as the top rig.
Don't know how much you already know, so apologies if i am telling you how to suck eggs.